A mezuzah is parchment scroll called a klaf on which the Shema is handwritten by a qualified scribe.
A mezuzah is affixed to the right doorpost of Jewish home in the upper third of the doorpost (i.e., approximately shoulder height), reminding us of G‑d and our heritage. It is also a symbol of G‑d's watchful care over the home. The placing of a mezuzah on the doors of a home or office protects the inhabitants — whether they are inside or outside. Where the doorway is wide enough, many Ashkenazi Jews tilt the mezuzah so that the top slants toward the room into which the door opens. This is done to accommodate the variant opinions of Rashi and of his grandson, Rabbeinu Tam, as to whether it should be placed vertically (Rashi) or horizontally (Rabbeinu Tam).
In our assortment you can find mezuzah cases of different sizes and styles as well as mezuzah parchment scrolls of 12 cm / 4.7’’ and 10 cm / 3.9’’. For car mezuzahs there is of course no halchic obligation, people like to offer them to friends to wish them a special protection while driving.